Deuteronomy 32:15

But Jeshurun waxed fat, and kicked: thou art waxen fat, thou art grown thick, thou art covered with fatness; then he forsook God which made him, and lightly esteemed the Rock of his salvation.

Jeshurun — Israel whom he calls right or upright, (as the word signifies) partly by way of instruction to mind them what they professed and ought to be; and partly by way of exprobration, to shew them what a shame it was to degenerate so much from their name and profession.

Kicked — As well fed cattle use to do: he grew insolent and rebellious against God and against his word and spirit.